Will I be able to paint over brown stain?

I moved into a cottage where the walls are an off white but everything else was painted dark brown about 15 years ago and has been neglected since. Brown kitchen cabinets, brown shutters, brown trim, brown doors - you get the picture! The owner of the house thinks I am not able to paint over the brown stain but PLEASE tell me he is wrong!!
Any and all suggestions are welcome. Thank you.

Barbie in Brown!
  10 answers